1. Field of the Invention
The present invention relates to digital acquisition and transmission of images and, more particularly, to a mobile device having a digital image sensor for capture and transmission of images, wherein the digital image sensor is preferably a digital pixel sensor (DPS).
2. Discussion of Related Art
The Internet is a rapidly growing communication network of interconnected computers around the world. Together, the millions of connected computers form a vast repository of hyperlinked information that is readily accessible by any of the connected computers from anywhere and anytime. To provide mobility and portability of the Internet, recent technologies have been introduced to make it possible for wireless mobile devices to communicate, via wireless data networks, with the computers on the Internet. Thus people on the go are able to be in communication with devices on the Internet as well as other people.
The most common information sharing paradigm is, as of today, a desktop computer coupled to the Internet. The desktop computer is equipped with one or more input devices that allow a user to generate information to be uploaded for sharing or distribution over the Internet. This paradigm may remain useful for a considerable number of applications and users, but there has been a growing need for a mobile paradigm in which the Internet can be accessed by mobile devices from anywhere at any time. Likewise the mobile devices are desired to provide information to be shared or distributed over the Internet.
Examples of mobile devices include cellular phones, personal digital assistants (PDAs), palm-sized computers, or lap-top computers. Currently, the kind of information that may be conveniently transmitted to and from such mobile platforms is voice and text information. Image exchange with mobile devices is usually more challenging. This is because image acquisition from mobile devices possesses some inherent problems. A simple integration of a CCD sensor or a conventional CMOS sensor with a mobile device provides images that often turn out too poor to have practical uses. One of the reasons is that a user of a mobile device moves around and experiences dynamically changed lighting conditions, for example, from sunshine to dark. Unless sophisticated and expensive optical designs are equipped, most of the CCD sensors or CMOS sensors in a mobile device are handicapped to the dynamics in the “mobile image acquisitions”.
In addition, many users of the mobile image acquisitions desire to rapidly capture images to record scenes of particular interests. Preferably, the mobile device itself does not have to store each of the images output from an image sensor therein to reduce the memory requirement therefor, hence the cost thereof. Captured images are desired to be transported off the mobile device as soon as the sensor can possibly readout the images, thus requiring a higher speed clocking signal to synchronize the operations of the sensor. Generally, the higher speed the clocking signal is, the higher power consumption the sensor would have, indeed an undesirable feature for a mobile device that operates on a battery of limited capacity.
Therefore, there is a great need for mobile devices equipped with image sensors that not only cope with the dynamically changing lighting conditions but also operate at a lower speed clocking signal while maintaining a high speed readout from the image sensor.